Marcus Hagerott | a89f523 | 2016-12-07 10:04:00 -0800 | [diff] [blame] | 1 | // Copyright 2016 Google Inc. All Rights Reserved. |
| 2 | package com.android.contacts.util.concurrent; |
| 3 | |
| 4 | import android.os.Handler; |
| 5 | |
| 6 | import com.google.common.util.concurrent.FutureFallback; |
| 7 | import com.google.common.util.concurrent.Futures; |
| 8 | import com.google.common.util.concurrent.ListenableFuture; |
| 9 | |
| 10 | import java.util.concurrent.CancellationException; |
| 11 | import java.util.concurrent.ScheduledExecutorService; |
| 12 | import java.util.concurrent.TimeUnit; |
| 13 | import java.util.concurrent.TimeoutException; |
| 14 | import java.util.concurrent.atomic.AtomicBoolean; |
| 15 | |
| 16 | /** |
| 17 | * Has utility methods for operating on ListenableFutures |
| 18 | */ |
| 19 | public class FuturesUtil { |
| 20 | |
| 21 | /** |
| 22 | * See |
| 23 | * {@link FuturesUtil#withTimeout(ListenableFuture, long, TimeUnit, ScheduledExecutorService)} |
| 24 | */ |
| 25 | public static <V> ListenableFuture<V> withTimeout(final ListenableFuture<V> future, long time, |
| 26 | TimeUnit unit, Handler handler) { |
| 27 | return withTimeout(future, time, unit, ContactsExecutors.newHandlerExecutor(handler)); |
| 28 | } |
| 29 | |
| 30 | /** |
| 31 | * Returns a future that completes with the result from the input future unless the specified |
| 32 | * time elapses before it finishes in which case the result will contain a TimeoutException and |
| 33 | * the input future will be canceled. |
| 34 | * |
| 35 | * <p>Guava has Futures.withTimeout but it isn't available until v19.0 and we depend on v14.0 |
| 36 | * right now. Replace usages of this method if we upgrade our dependency.</p> |
| 37 | */ |
| 38 | public static <V> ListenableFuture<V> withTimeout(final ListenableFuture<V> future, long time, |
| 39 | TimeUnit unit, ScheduledExecutorService executor) { |
| 40 | final AtomicBoolean didTimeout = new AtomicBoolean(false); |
| 41 | executor.schedule(new Runnable() { |
| 42 | @Override |
| 43 | public void run() { |
| 44 | didTimeout.set(!future.isDone() && !future.isCancelled()); |
| 45 | future.cancel(true); |
| 46 | } |
| 47 | }, time, unit); |
| 48 | |
| 49 | return Futures.withFallback(future, new FutureFallback<V>() { |
| 50 | @Override |
| 51 | public ListenableFuture<V> create(Throwable t) throws Exception { |
| 52 | if ((t instanceof CancellationException) && didTimeout.get()) { |
| 53 | return Futures.immediateFailedFuture(new TimeoutException("Timeout expired")); |
| 54 | } |
| 55 | return Futures.immediateFailedFuture(t); |
| 56 | } |
| 57 | }); |
| 58 | } |
| 59 | } |